Could an action swap change harmonics?!

[FEENIX]

I've been reloading for a little over ten years, many thousands of rounds everything from hunting to competition. I rigged up a new prs rifle last year, krg chassis, TT diamond, proof prefit 6 creed, Peterson brass n555 powder br2 primer 3110 fps SD of 9fps. It started out with a defiance anti action (20oz) and the thing absolutely hammered then when I got a tenacity action action (32oz) in I switched them and then it started shooting like . Headspace is exactly the same between the 2 actions, all the parts and components are the same lots, same good quality and consistent. Could the action change have threw my harmonics off enough to go from shooting .1-.2 to shooting 1moa?! Anyone else ran into this?

OK, I have to ask; I know you have to scratch an itch, but what were you drinking to finally change the action when you are getting .1-.2 MOA group?

 

[DENRIK89]

OK, I have to ask; I know you have to scratch an itch, but what were you drinking to finally change the action when you are getting .1-.2 MOA group?

I know right lol I had a defiance anti on hand I got for a lightweight hunting build then I decided to pop it on and do load development while I waited on a beefier action. That light weight Anti wasn't really made to thrash on all weekend shooting prs

 

[Beluebow]

I'm struggling with harmonics opening up .1-.2 groups to moa,not saying it couldn't happen I have plenty of experience with tuners changing group sizes and know it could happen. But having done several barrel swaps to different (indentical but different actions) and stocks with little change, it's certainly enough to make you go hmmm.

I would take a hard look at the differences between the two ignition systems.

 

[DENRIK89]

I'm struggling with harmonics opening up .1-.2 groups to moa,not saying it couldn't happen I have plenty of experience with tuners changing group sizes and know it could happen. But having done several barrel swaps to different (indentical but different actions) and stocks with little change, it's certainly enough to make you go hmmm.

I would take a hard look at the differences between the two ignition systems.

Has me dumbfounded too man, I was halfway through a batch of 50 rounds when I made the switch. Literally everything is the same but the action and bolt

 

[nealm66]

I recently put a .5 moa take off savage barrel on a friend's action while he was waiting for a carbon six barrel to arrive just to see how everything did and it didn't change enough that I could notice. Same load

 

[Buckys]

Apologies if I missed this - bedding, action lugs, stock, etc. - seems like another potentially important variable in the new system? Second order (or more) versus headspace, timing, etc. but still yet another important consideration. i.e., how is the bedding dampening harmonics?

 

[spladi]

I've been reloading for a little over ten years, many thousands of rounds everything from hunting to competition. I rigged up a new prs rifle last year, krg chassis, TT diamond, proof prefit 6 creed, Peterson brass n555 powder br2 primer 3110 fps SD of 9fps. It started out with a defiance anti action (20oz) and the thing absolutely hammered then when I got a tenacity action action (32oz) in I switched them and then it started shooting like . Headspace is exactly the same between the 2 actions, all the parts and components are the same lots, same good quality and consistent. Could the action change have threw my harmonics off enough to go from shooting .1-.2 to shooting 1moa?! Anyone else ran into this?

Did you say that the tenon's were the same too?

 

[DENRIK89]

Apologies if I missed this - bedding, action lugs, stock, etc. - seems like another potentially important variable in the new system? Second order (or more) versus headspace, timing, etc. but still yet another important consideration. i.e., how is the bedding dampening harmonics?

None that I can imagine except It's in a one piece aluminum chassis so it shouldn't need bedded by I think I'm going to and see how that shakes out

 

[DENRIK89]

Did you say that the tenon's were the same too?

Yes it's the same barrel

 

[Mikecr]

Beluebow at post #17 has a good point. The striking with that new action/trigger could depart from optimum for the chosen primer.

 

[The Oregonian]

Has me dumbfounded too man, I was halfway through a batch of 50 rounds when I made the switch. Literally everything is the same but the action and bolt

Which means the whole thing is new. It's like saying that everything on my car is the same except the chassis, and I can't figure out why it performs differently. It is a new rifle at this point.

 

[DENRIK89]

Seating depth test and back where it needs to be!

 

[FEENIX]

Seating depth test and back where it needs to be!

Excellent! As @QuietTexan noted,

You built a new rifle, work up accordingly.

 

[loonie]

I have several LR bench guns with the same brand and model action and barrels chambered with the same reamer. I swap barrels and they might not shoot a known load because that action prefers a certain primer. It could be the difference in ignition. I have swapped bolts in a action shooting groups on paper at 1000 yards and one will shoot good and the other one bad. I believe its the difference in firing pin strike.